The present invention is directed to waste material treatment devices, and more particularly to a compression device for feeding a waste material to a reactor.
Various reactor feed and waste treatment devices are currently available in the industry. U.S. Pat. Nos. 3,841,465 and 4,312,279 disclose reactor feed devices. These devices operate to produce a steady flow of material to the reactor, with varying methods of compaction. These conventional devices are not satisfactory, however, in that they are not versatile enough to process and adequately compress a wide range of waste materials. U.S. Pat. Nos. 4,915,308; 5,108,040 and 5,320,034 disclose waste treatment devices that utilize a compression auger-screw to shred and compact various waste forms for disposal and further processing. These conventional devices are also not satisfactory since they are commonly limited to a fixed compression ratio no greater than 3:1 and they possess no jamming prevention mechanism. Furthermore, none of the aforementioned devices adequately maintains an air-seal for use with the currently utilized thermal treatment reactors. U.S. Pat No. 5,088,422 discloses a rotary isolation door for separating a waste stream feed from the reactor chamber. This single opening design produces excessive wear on the single annular cutting surface, requiring frequent loss of processing time for replacement. Additionally, it depends on relatively high-maintenance hydraulics for operation and does not have control mechanisms for precise operation.
In view of the various drawbacks associated with individual conventional devices, there is a need in the industry for a variable compression device to compress or compact a variety of waste feed materials and which is compatible with a conventional thermal treatment reactor. Furthermore, none of the aforementioned patents disclose or suggest the combination of elements or methods that are considered to make the present invention patentable, workable and advantageous for a compression device and feeder for a thermal treatment reactor.
The principal object of the present invention is to provide a compression device for feeding a waste material to a reactor which has the capability to process various materials within a wide range of densities and compressibilities.
An object of the present invention is to provide a compression device for feeding a waste material to a reactor that could be used for the purpose of handling, treatment, or disposable of hazardous materials, radioactive waste, mixed waste, medical waste, municipal waste, and long-term stored waste.
Another object of the present invention is to provide a compression device for feeding a waste material to a reactor wherein the entire system creates a seal between the prepared waste and the thermal treatment reactor or system.
Yet another object of the present invention is to provide a compression device for feeding a waste material to a reactor which detects potential problems with the auger-screw assemblies prior to any occurrences and provides immediate, programmed corrective action. In particular, the device of the present invention includes a logic component that, upon detection of a jamming condition of the auger-screw assemblies, alerts the operator and follows a series of corrective sequences to eliminate the jamming conditionxe2x80x94shutting-down the device only when absolutely necessary. This arrangement reduces the frequency of downtime and the necessity of the operator-interference thereby significantly reducing the efforts on the part of the operator.
An additional object of the present invention is to provide a compression device for feeding a waste material to a reactor which is highly reliable in that it monitors and controls rotational speeds and rotational directions of both the feed and compaction auger-screws thereby preventing a jamming condition well in advance of its occurrence.
Another additional object of the present invention is to provide a compression device for feeding a waste material to a reactor that is easy to disassemble for cleaning, repair and maintenance.
Yet an additional object of the present invention is to provide a compression device for feeding a waste material to a reactor which is self-draining towards the reactor for any liquid component in the waste material.
Still yet an additional object of the present invention is to provide a compression device for feeding a waste material to a reactor in which the feed auger-screw and the compression auger-screw are arranged at right angles to each other to thereby prevent any stress concentrations on the initial flight of the compression auger-screw.
Still yet an additional object of the present invention is to provide a compression device for feeding a waste material to a reactor which can be completely isolated from the reactor by closing the shut-off valve and disassembling the flange joint therebetween. This arrangement allows the reactor to continue its operation during maintenance on the compression device.
A further object of the present invention is to provide a compression device for feeding a waste material to a reactor which has the capability of reaching a compressional ratio of over 5:1.
Yet a further object of the present invention is to provide a compression device for feeding a waste material to a reactor which utilizes the full cutting surfaces of all the shear-cutting ports in clockwise and counter-clockwise directions. This arrangement substantially increases longevity of the shear-cutting surfaces and significantly reduces repair and maintenance.
Still yet a further object of the present invention is to provide a compression device for feeding a waste material to a reactor in which the feed-discharge gate valve is automatically closed by a programmable logic controller (PLC) via an electrical interlock.
Still yet a further object of the present invention is to provide a compression device for feeding a waste material to a reactor in which the feed-discharge gate valve provides positive gas sealing in the event compacted waste sealing is not available, to thereby prevent reactor gases from flowing back into the hopper and possibly out of the device where they may be hazardous to the operating personnel.
Yet an additional object of the present invention is to provide a compression device for feeding a waste material to a reactor which, in the event of a catastrophic tight jamming of an auger-screw, allows for easy removal of the total auger-screw assembly. This relieves the jam, allows for replacement of an auger-screw, if necessary, and allows for a thorough cleaning of all internal areas. The overall end result is that the production downtime is significantly reduced.
Still yet an additional object of the present invention is to provide a compression device for feeding a waste material to a reactor which satisfies nuclear safety considerations of requiring the maintenance personnel to perform various servicing operations utilizing gloves through glovebox ports.
In accordance with the present invention, a compression device for feeding a waste material to a reactor includes a waste material feed assembly having a hopper, a supply tube and a compression tube. Each of the supply and compression tubes includes feed-inlet and feed-outlet ends. A feed-discharge valve assembly is located between the feed-outlet end of the compression tube and the reactor. A feed auger-screw extends axially in the supply tube between the feed-inlet and feed-outlet ends thereof. A compression auger-screw extends axially in the compression tube between the feed-inlet and feed-outlet ends thereof. The compression tube is sloped downwardly towards the reactor to drain fluid from the waste material to the reactor and is oriented at generally right angle to the supply tube such that the feed-outlet end of the supply tube is adjacent to the feed-inlet end of the compression tube. A programmable logic controller is provided for controlling the rotational speed of the feed and compression auger-screws for selectively varying the waste material feed and the compression of the waste material.